A radiation measuring device for luminescence measuring is known, for example, from U.S. Pat. No. 4,772,453. The basic principle of the arrangement therein disclosed is a fixedly disposed radiation detector which successively receives luminescence signals from individual sample containers conducted underneath an entrance window and a reflection optical device, particularly as shown in FIG. 11 of that patent. In this case, M.times.N sample containers are located on a common holder plate which can be displaced in the x-y plane by means of suitable guide rods and associated drive elements in such a way that every single sample container on the holder plate comes to rest underneath the entrance window of the radiation detector. The displacing devices required for this take up a fairly large space and must be exactly aligned with each other so that the proper association between the sample container and the entrance window is achieved in a dependable manner and in exact steps for each of the sample containers. Therefore this plurality of guide elements, such as guide rails and guide sleeves sliding thereon, must be manufactured and assembled with high mechanical precision (or within correspondingly low tolerance limits) so as to somewhat assure this dependable association and also to reduce disruptions because of mutual obstruction of the x-y displacements, for example by tilting or binding, to a minimum.
Devices for additional vertical movements of the detector require that their movement paths be coordinated with the movement paths of the components responsible for the horizontal displacement of the recording plate in the x-y plane, which therefore leads to further structural complications.
Apparently the problems in regard to the known displacement devices have already been recognized; however, a solution was apparently seen (as also suggested in European Patent Disclosure EP-A-0 181 060) to lie in conceiving a measuring device with a plurality of detectors disposed in rows (European Patent Disclosure EP-A-0 025 350; German Published, Non-Examined Patent Application DE-OS 31 10 239) which, although it allows for a simpler, one-dimensional displacement of the sample holder, entails a disproportionately large expenditure for component parts. Thus, this prior art proposes a plurality of radiation detectors instead of a solution to the problems associated with a displacement device.
A comparison of the two mentioned references shows that the basically desirable properties of a structurally simple construction on the one hand and light-tight shielding of the critical connecting area between sample container and radiation detector in the measuring position, on the other, cannot be realized by means of the suggested solutions, or that at least no concrete way of accomplishing this is discernible from the prior art.